Many operations inside the abdominal cavity are currently performed by laparoscopy, a minimally invasive procedure associated with decreased risk, shorter recovery time and improved aesthetics (fewer scars, etc.). In performing a laparoscopy procedure, a rigid viewing apparatus (laparoscope) is inserted via a small incision adjacent to the umbilicus, and one or more accessory punctures are used to introduce various treatment tools for grasping, cutting, suturing and achieving hemostatic control. Safe and effective laparoscopic surgery requires having a clear view of the area and target to be treated, and the availability of a variety of tools (some of which may be energized) to perform the surgical procedure. The laparoscope and the treatment devices are generally introduced into the abdominal cavity via trocars which provide a port of entry.
Recently, the trend towards minimally invasive surgery (MIS) has taken further steps to further minimize the extent of abdominal wall scarring while maintaining a high level of efficacy and user control. Procedures which are part of this approach include single port or single trocar laparoscopy, natural orifice translumenal endoscopic surgery (NOTES) and robotic surgery. These procedures require new tools with added maneuverability, especially to facilitate the ability to rotate the treatment tip and add spatial degrees of freedom to the tool's tip. This added flexibility enables performing surgical procedures (in the abdomen and other areas of the body) using a single trocar through which several surgical devices/instruments, including a laparoscope or an endoscope, are passed into the abdominal cavity.
One of the advantages of using laser waveguides is their flexibility. Specifically, laser waveguides can be deflected to a radius of several centimeters, depending on the waveguide diameter, materials the waveguide are made from and other structural characteristics. While hollow waveguides are less flexible than solid fibers, the advantage of hollow wave guides is their capability to deliver long wavelengths in the IR range, for example, CO2 and Er:YAG wavelengths radiation with high power. Because CO2 lasers are considered to be the ideal laser scalpel, the ability to use waveguides to deliver CO2 radiation is important for laparoscopic and other surgical procedures.
Laser surgery uses a high energy laser radiation beam which can, for example, cut, ablate and/or coagulate the tissue. The efficiency, precision and resultant minimal collateral damage characterizing laser devices make them suitable for use in laparoscopic procedures, as well as other types of procedures, in a manner similar to the way laser-based devices have become widespread in performing various surgical procedures in a variety of medical specialties. For example, laser assisted laparoscopic surgery has been performed by transmitting laser radiation, e.g., generated by CO2 lasers, via a straight rigid laparoscope. However, use of such a laparoscope to enable laser-based operations puts limitations on the procedure.
A challenge associated with the use of laser energy to perform procedures is the risk of damage that may be caused to surrounding non-targeted tissue. For example, a CO2 laser beam exiting a hollow waveguide can be of high energy and be minimally dispersing with distance (and therefore may have an advantage over traditional RF or ultrasound based instruments), but, however, carries a risk when the laser beam unintentionally hits a non targeted tissue. To overcome this risk, a backstop protector is sometimes used where the treated tissue is placed between the laser waveguide tip and the backstop. However, as the tissue is being cut, stray laser radiation may hit the backstop and a gradual effect of heating is induced. In turn, heat conduction processes may cause heat to be delivered from the backstop to the tissue and may thus cause collateral damage to the tissue, as well as cause the tissue to stick to the backstop.
It is to be noted that unlike RF or ultrasound based instruments, where the direct heat transfer from the heated part of the tool to the tissue is the mechanism which causes the treatment effect (e.g., either cutting or coagulating), the laser energy does not require such conduction, and in fact the tissue is “floating” and can be cut from a distance.
A further challenge involved with using laser energy in procedures (e.g., surgical procedures) is the delivery of laser energy in conjunction with the use of other tools (e.g., graspers) to manipulate the tissue. For example, in treating tissue, grasping instruments (or graspers) may sometimes be used. Implementations of grasping laparoscopic instruments include instruments that have a hollow shaft with a typical outer diameter of 5 mm which has a controlling handle at its proximal side and a treating tip coupled to the shaft's distal end. The treatment tip generally has one or two moveable jaws which may be closed against each other using the controls at the handle. In more advanced instruments, an additional hinge may be placed at some distance from the tip which enables bending the tip with respect to the instrument's shaft at angles of up to about 90°. Such a structure requires passing a laser waveguide inside the instrument's main shaft, and allowing it to be bent at the flexible hinge proximal to the instrument's tip. The limited bending angle of the waveguide and the limited space available at the treatment tip to deflect the beam make it difficult to implement scanning movement of radiation, either linear or radial (rotational), of the beam over the target tissue.